CMB statistical isotropy confirmation at all scales using multipole vectors.

We present an efficient numerical code and conduct, for the first time, a null and model-independent CMB test of statistical isotropy using Multipole Vectors (MVs) at all scales. Because MVs are insensitive to the angular power spectrum C ℓ , our results are independent from the assumed cosmological model. We avoid a posteriori choices and use a pre-defined range of scales ℓ ∈ 2 , 30 , ℓ ∈ 2 , 600 and ℓ ∈ 2 , 1500 in our analyses. We find that all four masked Planck maps, both from the 2015 and 2018 releases, are in agreement with statistical isotropy for ℓ ∈ 2 , 30 , ℓ ∈ 2 , 600 . For ℓ ∈ 2 , 1500 we detect anisotropies but this is indicative of simply the anisotropy in the noise: there is no anisotropy for ℓ < 1300 and an increasing level of anisotropy at higher multipoles. Our finding of no large-scale anisotropies seem to be a consequence of avoiding a posteriori statistics. We also find that the degree of anisotropy in the full sky (i.e., unmasked) maps vary enormously (between less than 5 and over 1000 standard deviations) among the different mapmaking procedures and data releases. [ABSTRACT FROM AUTHOR]